<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    *{
        margin:auto;
    }
    .container{
        /* 给左右两栏腾出空间 */
        padding-left:200px;
        padding-right:200px;
    }
    .conter{
        width:100%;
        height:500px;
        background:plum;
        float:left;
    }
    .left{
        width:200px;
        height:400px;
        float:left;
        background: pink;
        margin-left:-100%;
        position: relative;
        left:-200px;
    }
    .right{
        width:200px;
        height:400px;
        background: orange;
        float:left;
        margin-left:-200px;
        position: relative;
        right:-200px;
        /* margin-right:-100%; */
    }
</style>
<body>
    <div class="container">
        <div class="conter">
            <h2>圣杯布局</h2>
        </div>
        <div class="left"></div>
        <div class="right"></div>
    </div>
</body>
</html>